Safety device for conveyer supports



Nov. 29, 1949 L, c. BACKART 2,489,947

SAFETY DEVICE FOR CONVEYER SUPPORTS Filed Oct. 1, 1945 INVENTOR LLOYD C.BAG/(ART Patented Nov. 29, 1949 UNITED STATES PATENT OFFICE SAFETYDEVICE FOR CONVEYER SUPPORTS Lloyd 0. Backart, Grand Rapids, Mich,assignor to The Rapids-Standard Company, Inc, Grand Rapids, Mich., acorporation of Michigan 7 Application October 1, 1945, Serial No.619,592

Claims.

This invention relates to a safety device for a conveyer having avertically adjustable supporting frame and more particularly to a safetydevice which may be incorporated into the construction of such a frameto prevent its improper collapse.

The conventional type of mobile gravity and/ or power conveyer isusually manually adjustable through a range of varying heights anddegrees of inclination. Injuries have, from time to time, resulted fromthe use of this type of conveyer by the improper collapse of thesupport. In one type of such conveyer a pair of rails is fitted with acollapsible support which is secured in any desired manner to form arigid holding thereof at a desired vertical adjustment. This is usuallydone by means of a pair of fastenings, one on each side of the rails,which must be manually operated. If a careless operator negligentlyreaches under the support to loosen for lowering the far side withoutfirst making certain that the near side is tightened, the rails maycollapse and catch a portion of the operators arm or body between therails and the support. It is one of my aims to prevent this hazard bymeans of a device which will render the support only partiallycollapsible, which may be readily added to any such conveyer now in use,and which is simple and economical to manufacture.

Therefore, a principal object of my invention is to provide a safetydevice for use on conventional conveyers which have a collapsiblesupport.

A further object of this invention is to provide a safety device for useon a conventional type of collapsible support for a conveyer, whichdevice will prevent injuries which otherwise may occur when saidconveyer is poorly adjusted.

Another object of this invention is to provide a safety device which maybe adapted to conveyers having a wide range of support mechanisms andwhich may be readily added thereto.

Another object of this invention is to provide such a safety devicewhich comprises few movable parts and which is economical tomanufacture.

The details of my invention may be seen from the accompanying drawing.wherein:

Figure 1 is a fragmentary perspective view .of one type of gravityconveyer and its collapsible support fitted with an adjusting mechanismand. my improved safety device.

Figure 2 is a fragmentary front elevation of the spring and pivot of thesafety device installed in place.

Figure 3 is a view, mostly in a cross-section, taken on the line IIIIIIof Figure 2.

Figure 4 is a fragmentary side elevation of the spring and pivot.

This invention comprises an improvement on the adjustable type ofcollapsible support for a conveyer, one type of which is described inReissue Patent 23,079, essentially as shown in Figure 1. Referring thento this figure, a conveyer of this type comprises a pair of rails, inand H, spaced apart evenly by a plurality of shafts l2 welded to therails. These shafts are each encased by a free running roller I3 overwhich the work is conveyed from the upper to the lower end of theconveyer by the force of gravity.

This conveyer is equipped with a retractable support by which the heightand/or angle of inclination of the conveyer may be varied. Referringagain to Figure 1, this support comprises a pair of tubular frame or legmembers l4 and I5 which are spaced apart in a parallel manner by atleast two transverse tubular members l6 and l'i. The upper transversetubular member I6 is rotatably disposed between the rails Ill and II.The lower transverse tubular member I1 is provided with a pair ofrollers l8 which provide mobility to the conveyer.

' The rightward end of the conveyer proper, as shown in Figure l, isprovided with a transverse tubular member l9 which is rotatably disposedwithin channel bar housings 20 and 20a at either end, each housing beinglongitudinally slidable on the rails l0 and II. Independent manuallyoperable gripping means for holding these housings in selected positionson the rails is provided by gripping cams. The respective housings areconnected by a cooperating shaft 22. The gripping cams on each side aremoved as desired by independent means, as cranks, of which one appearsat 2|. Further details of construction of this type of conveyer, supportand holding means to which my invention is applicable may be found in U.S. Reissue Patent 23,079.

A supporting member or second leg in the form of longitudinal linkmember 23 is supported at its upper end by being pivotally mounted ontothe housings 2i! and'20a in any convenient manner as by being welded tothe tubular member I9 which pivotally surrounds a bar welded betweensaid housings. Its other end is connected to a tubular casing 24, which,is in turn, rotatable about a shaft 25. This shaft is immovablyconnected to the longitudinal frame members l4 to the frame members I 4and I5.

26a of said frame members. A flat coil spring 21 is bent at the extremeinner end and hooked over a bead 28 projecting outwardly from thesurface of the tubular casing 24, and held at its outer end by a curvedportion hooked over a spring holding shaft 29. Tension on this springmay be secured and adjusted by placing each adjacent end of the springholding shaft 29 into one of a plurality, as three, openings containedin a rounded flange 30 welded to and downwardly extending from each ofthe tubular members 14 and i at points close to the points of fasteningof the lugs 26 and 26a. In the preferred form shown, these flanges areeach opposite thesupporting frame member l4 or IE from the corresponuinglug 26 or 26a, respectively. With the means which grip the slidablehousings 2i] and 26a to the side rails properly loosened, the conveyorincluding said side rails is in a position to move downwardly upon anormally, freely collapsing frame. As it does so the link member 23 willrotate upon its pivot clockwise with respect The spring will oppose butnot prevent this motion. A corresponding spring 2'la may be similarlyinstalled at the other end from spring 211 of the sleeve 24.

If the springs are normally shaped so that they will be but slightlydistorted when the adjustable frame is in its full upward position, itwill be found that the installation of these springs may be effectedquickly and easily. These springs may be selected of such stiffness thatthey will balance the weight of the conveyer at any desired point. Ihave found, however, that it will require a pair of springs of onlymoderate size to support the weight of an unloaded conveyer of usualsize when the supporting members have moved to an approximately half-waycollapsed position. At this point the above mentioned rotation of thelink 23 with respect toframe members l4 and i5 will have placedsufiicient tension upon the springs that further such rotation will beresisted so long as the collapsing motion is'induced by only the normalweight of the ordinary conveyer. With balance secured at this point, anoperator may easily move the conveyor proper upward with the aid of thesprings or push it further downward against the springs and hold it inthe desired position with one hand while with the other hand he sets themanually operated gripping means on at least one side.

Since the major load of the conveyer is taken by the springs and sincethe conveyer cannot, of its own weight, fall beyond a predetermined andknown balance point, the operator can move the conveyer frame at willupwardly or downwardly and be secure in the knowledge that it will notfall into a fully collapsed condition if it should happen to slip out ofhis immediate manual control.

It will be evident also that this safety device will function as meansfor assisting the ease with which the conveyer may be adjusted upwardlyor downwardly.

Various modifications may be made in the above described device all ofwhich will be included within the hereinafter appended claims exceptingas said claims by their own terms expressly provide otherwise.

I claim:

1. Safety means for conveyer supporting frame members wherein one ofsaid members is mounted to another of said members for pivotal movementwith respect to each other as the body of said conveyer is adjustedupwardly and downwardly, said means comprising: a resilient elementcoiled upon itself and positioned co-axially with the point of pivotalattachment of said members with respect to each other, the inner end ofsaid element held against motion with respect to one of said members andthe outer end held against motion with respect to the other of saidmembers, said element resiliently opposing such relative pivotalmovement as the body of said conveyor is adjusted downwardly.

2. A safety means associated with conveyor construction having aconveyor frame supported by a pair of leg members attached to each otherat a point substantially removed from said conveyor frame for pivotalmovement relative to each other, the end of one member of said pairbeing pivoted to a member slidably adjustable along a member of theconveyor frame, and the end of the other member of said pair pivotallyaffixed to said conveyor frame; said safety means comprising: aresilient member under tension aflixed at one part thereof rigidly withrespect to one of said leg members and affixed at another part thereofrigidly with respect to the other of said leg members, the urging ofsaid resilient member opposing pivotal separation of said leg membersabout said point of pivotal attachment as said conveyor frame isadjusted downwardly.

3. Safety means for a conveyor having a pair of rails spacedly securedtogether and means supporting said spaced rails at selectively andadjustably variable heights, said supporting means comprising: a firstleg member secured at its upper end in pivotal relationship to one ofsaid rails, a second leg member pivotally and slidably secured at itsupper end to said rail and pivotally secured to said first leg member ata point spaced from said upper end; said point of pivotal attach ment ofsaid first leg member and said second leg member being spaced from theupper end of said first leg member, said leg members moving pivotallywith respect to each other as the said rails are moved upwardly anddownwardly; the safety means comprising: a resilient element coiled uponitself, the inner end of said element held against motion with respectto one of said leg members, and the outer end held against motion withrespect to the other of said leg members, said element resilientlyopposing relative pivotal movement of said leg members as the body ofsaid conveyor is adjusted downwardly.

4. Safety means for a conveyor supporting frame wherein said supportingframe includes a leg member and a link member, said link member mountedon one of its ends to said leg member at a point substantially removedfrom either end of said leg member for pivotal movement relative to saidleg member as the body of said conveyor is adjusted upwardly anddownwardly, said link member on the other of its ends slidably mountedto the body of said conveyor, said means comprising: a resilient membercoiled upon itself and positioned .co-axially with the point of pivotalattachment of said leg member and said link member, the inner end ofsaid element held against motion relative to said link member, the outerend of said element held against motion relative to said leg member,said element resiliently opposing pivotal motion of said leg member andlink member relative to each other as the body of said conveyor isadjusted downwardly.

5. Safety means for a conveyor supporting structure wherein saidsupporting structure includes a leg member pivotally attached at a pointsubstantially removed from each of its ends to a upwardly anddownwardly; a helical resilient member co-axial with said shaft andhaving its inner end held against motion relative to said shaft and itsouter end engaging and held against motion relative to said bar, thepositioning of said resilient member being such as to cause saidresilient member to oppose relative movement of said leg member and saidsupporting member as the body of the conveyor is adjusted downwardly.

LLOYD C. BACKART.

No references cited.

